The studies proposed for this component of the program project follow directly from the investigator's continuing work describing the development of communication of non-speaking children with mental retardation. Research will focus on an important but understudied aspect of early conversation skills repair of communication breakdown. Research will focus on an important but understudied aspect of early conservation skills repair of communication breakdown. Children who communicate with gestures and vocalizations are at risk for experiencing communication breakdowns as they communicate with their mothers. Study 1 will investigate the hypothesis that children who differ in gesture use will also differ in their use of repair strategies. Forty two children will be observed in two contexts: interacting with their mothers and interacting with an experimenter in a scripted protocol. The communication breakdowns and repairs by four groups of 10 children will be compared. Groups will differ according to gesture and speech production. In addition to comparing group differences, we will analyze the relative effectiveness of different signals of communication breakdown in resolving breakdowns. Study 2 will attempt to alter the occurrences of specific types of communication breakdowns. Ten dyads that experienced relatively frequent breakdowns in Study 1 will be asked to participate in Study 2. Intervention will focus on teaching parents to identify communication breakdowns and to change the means used to indicate a communication breakdown. The specific strategies taught to parents will be based on the results of Study 1. The results of these two studies will contribute to the existing knowledge base regarding early communication development and interventions that may significantly alter communication effectiveness.